<!DOCTYPE html>
<html>
<head>
  <meta charset="utf-8">
	<title>Phasing</title>

	<meta name="viewport" content="width=device-width, initial-scale=1, maximum-scale=1">
	<link rel="icon" type="image/png" sizes="174x174" href="./favicon.png">

	<script src="https://cdnjs.cloudflare.com/ajax/libs/webcomponentsjs/2.4.3/webcomponents-bundle.js"></script>
	<link href="https://fonts.googleapis.com/css?family=Material+Icons&display=block" rel="stylesheet"/>
	<script src="../build/Tone.js"></script>
	<script src="./js/tone-ui.js"></script>
	<script src="./js/components.js"></script>
</head>
<body>
	<style type="text/css">
		#loop {
			margin-bottom: 10px;
			display: flex;
		}

		#loop .bar {
			flex-grow: 1;
			width: 40%;
			height: 20px;
			margin: 10px;
			background-color: #ececec;
			border-radius: 4px;
			overflow: hidden;
			position: relative;
		}

		#loop .bar .fill {
			height: 100%;
			width: 50%;
			background-color:#7F33ED;
			position: absolute;
			left: 50%;
			transform: translate(-50%, 0);
		}
	</style>
	<tone-example label="Piano Phase">
		<div slot="explanation">
			By slightly slowing down the playbackRate of the Tone.Sequence in the right channel,
			the two identical melodies phase against each other in interesting ways.
			<br><br>
			Composition by Steve Reich. Inspiration from Alexander Chen.
		</div>

		<div id="content">
			<div id="loop">
				<div class="bar">
					<div class="fill"  id="left"></div>
				</div>
				<div class="bar">
					<div class="fill" id="right"></div>
				</div>
			</div>
			<tone-play-toggle></tone-play-toggle>
		</div>
	</tone-example>

	<script type="text/javascript">
		// set the bpm and time signature first
		Tone.Transport.timeSignature = [6, 4];
		Tone.Transport.bpm.value = 180;
				
		// L/R channel merging
		const merge = new Tone.Merge();

		// a little reverb
		const reverb = new Tone.Reverb({
			wet: 0.3
		});

		merge.chain(reverb, Tone.Destination);

		// left and right synthesizers
		const synthL = new Tone.Synth({
			oscillator: {
				type: "custom",
				partials: [2, 1, 2, 2],
			},
			envelope: {
				attack: 0.005,
				decay: 0.3,
				sustain: 0.2,
				release: 1,
			},
			portamento: 0.01,
			volume: -20
		}).connect(merge, 0, 0);
		const synthR = new Tone.Synth({
			oscillator: {
				type: "custom",
				partials: [2, 1, 2, 2],
			},
			envelope: {
				attack: 0.005,
				decay: 0.3,
				sustain: 0.2,
				release: 1,
			},
			portamento: 0.01,
			volume: -20
		}).connect(merge, 0, 1);

		// the two Tone.Sequences
		const partL = new Tone.Sequence(((time, note) => {
			synthL.triggerAttackRelease(note, "8n", time);
		}), ["E4", "F#4", "B4", "C#5", "D5", "F#4", "E4", "C#5", "B4", "F#4", "D5", "C#5"], "8n").start();

		const partR = new Tone.Sequence(((time, note) => {
			synthR.triggerAttackRelease(note, "8n", time);
		}), ["E4", "F#4", "B4", "C#5", "D5", "F#4", "E4", "C#5", "B4", "F#4", "D5", "C#5"], "8n").start("2m");

		// set the playback rate of the right part to be slightly slower
		partR.playbackRate = 0.985;

		// bind the interface
		document.querySelector("tone-play-toggle").addEventListener("start", () => Tone.Transport.start());
		document.querySelector("tone-play-toggle").addEventListener("stop", () => Tone.Transport.stop());

		// update the width of the fill bars to reflect the left and right progress
		function progressToWidth(progress) {
			progress = Math.cos(progress * Math.PI * 2 + Math.PI);
			progress = (progress + 1) / 2;
			return `${progress * 100}%`;
		}
		function loop() {
			requestAnimationFrame(loop);
			// make it go out and back for each loop
			// @ts-ignore
			document.querySelector("#left").style.width = progressToWidth(partL.progress);
			// @ts-ignore
			document.querySelector("#right").style.width = progressToWidth(partR.progress);
		}
		loop();
		
	</script>
</body>
</html>
